What's the best 45 (if you look at both sides, not just the A side) ever released? I doubt if there are any that come close to these two:

The Beatles - Strawberry Fields Forever/Penny Lane
The Beach Boys - God Only Knows/Wouldn't It Be Nice

Agree Joost The Beatles Strawberry Fields Forever /Penny Lane , tops anything .
But one other single from 1967 comes very close to it in my opinion , i doubt anyone will have heard it though.
John's Children :
" Midsummer Night Scene / Sara Crazy Child " , which is a unbelievable piece of psychedelic rock penned by a 19 year old Marc Bolan in his pre Tyrannosaurus Rex days.
This record is the Holy Grail for record collectors only a hand full were released and a copy will set you back thousands of pounds .
If you have not heard this record track it down it's brilliant , it's the great lost 60's single  

John's Children


DaveRam

bye bye miss american pie sides one is part one side 2 part 2

" Life On Mars /Man Who Sold The World " , David Bowie, was a pretty cool 45 from 1973.

Best from a women was
  " Wuthering Heights /Kite " ,Kate Bush , 1978 .
An extradinary debut , never heard another women come close to this record or many men  

DaveRam

I would say:

The Beatles - Strawberry Fields Forever / Penny Lane
Bob Dylan - Like A Rolling Stone / Gates of Eden
The Beach Boys - God Only Knows / Wouldn't It Be Nice

Stones:
Honky Tonk Women/You Can't Always Get What You Want
Brown Sugar/b****
Happy/All Down the Line

Big Star:
When My Baby's Beside Me/In the Street
September Gurls/Mod Lang

RICHARD & LINDA THOMPSON
Bright Lights /When I Get To The Border

The Clash
London Calling / Armagideon Time

The Doors
Light My Fire/The Crystal Ship

HEY JUDE / REVOLUTION  for me

E.L.O.
MR BLUE SKY/ ONE SUMMER DREAM
  

Quoted from mr kite

HEY JUDE / REVOLUTION  for me

Yes, completely agree  

She Loves You / I'll get You - The Beatles (i think the best pop single EVER!!! )

I Want To Hold Your Hand / This Boy  - The Beatles

Waterloo Sunset / Act Nice & Gentle - The Kinks

How Soon Is Now / Well I Wonder - The Smiths

Won't Get Fooled Again / I Don't Even Know Myself - The Who

Hung On You/Unchained Melody- The Righteous Brothers

Detroit Rock City/Beth come to mind from the mid 70s.

now you're talking...i remember wearing the hell out of the night chicago died by paper lace and barroom blitz...and then there was the theme from billy jack..i always dug that tune...righteous sounding ...go ahead and hate your neighbor go ahead and cheat a friend do it in the name of heaven on the bloody morning after(then it gets wild man duhn duhn duhn duhn duhn)  one tin soldier rides away,then there was the damn billy don't be a hero by bo donaldson and the heywoods..thank the stars fm radio was a sucess and what of melaines 45s??????

Not to mention Sweet's Little Willie, Carl Douglas Kung Fu Fighting and of course Lobo's Me and You and a Dog Named Boo.

Yessssssss!!!!! I have all of those songs on a bubblegum mix I made! Although I don't listen to it very much. I guess too much bubblegum at one time can be bad.

if i can recall correctly my most played 45 as a teen was band on the run....no beatles 45 was played more than nowhere man...but i think i spun pauls more.....and when w2e shindigged somebody at the party always had that in their collection...